I didn't expect it from a vitamin but the nausea is the worst. As far the burping goes, it's the strangest side effect I've ever had and it's the only thing that's changed in my regimen. Since taking this, I have weird gas that doesn't result in farting or anything but burping like a maniac and wanting to puke often. I feel bloated a lot and I just don't understand how something like this even happens or is possible. I've taken vitamin d3 supplements from other brands regularly prior to buying this and had zero problems AND yes, I eat when I take this. I can't imagine that it's only affecting me because this is quite odd. I was excited about the product because of the price but I think this bottle has to go in the trash unfortunately or I'll return it if possible. What a shame